The present invention is directed to the recovery of metallic lead from battery paste. In the recovery of metals and more in particular lead from batteries various methods have been proposed. In view of the restrictions posed on the disposal of spent batteries, which restrictions are due to the presence of heavy metals therein, it is of importance to recover these metals, and more in particular lead therefrom.
Spent batteries can be comminuted, followed by separation of the lead containing components from the remainder of the battery, mainly plastics. The lead containing components are obtained in the form of a pasty product, battery paste. This battery paste consists mainly of salts and oxides of lead in particle form, together with an amount of water. The predominant components in the battery paste are lead(II)sulphate, lead(II)oxide and lead(IV)oxide.
Up to now recovery of lead from battery paste was usually done in a pyro-metallurgical process, by treatment of the paste with coke and iron-(III)-oxide at high temperature. In this process metallic lead was obtained, together with various iron salts, such as FeS. Unfortunately, in this process also some SO.sub.2 could be produced. As the iron salts are chemical waste and the production of SO.sub.2 is undesirable, alternatives for the pyro-metallurgical processes are required.